Ear number per stalk?

As grown by farmers in most of the USA, each stalk has one ear.
But the same hybrids, if planted at much lower density (more space per plant)
likely will have two ears, or even more. When spacing is so great that each
plant has about one square meter of growing space, I've seen up to four ears
on the main stalk, and two tillers, each with one ear. But this is unusual.
Best yields in today's hybrids come when they are planted at densities that
allow not more than one ear per plant, on average.
Don Duvick